DONNA – Donna ISD police are preparing for the upcoming school year with the help of U.S. Customs and Border Protection.

They're training with CBP officers to prepare for an active shooter situation.

CBP officers have to be prepared for an array of threats at ports of entry. For the first time, they're training how to respond to a school.

Donna ISD's new police chief, Daniel Walden, said it's important for federal and local law enforcement to train together.

"It's just to prepare them for an active shooter situation. It doesn't have to occur at a school," he said. "A school is a setting where it can happen, but it can happen at Walmart, it can happen anywhere where there are a lot of civilians."

This week's training is going on at Runn Elementary.

During the school year, usually just one ISD police officer is on duty at the school.

If an active shooter situation were to happen there, Walden said that Donna ISD officer's closest back-up would be a CBP officer at the Donna-Rio Bravo International Bridge, located right across the road.

"So, if an active shooter was to happen, they would be the first ones here even before our other officers were here," Walden said.

Donna ISD employees posed as students and as the shooter. The trainees used guns with rubber rounds to make the situation as real as possible.

"So, it's a matter of training the proper way, and also putting them under stress in a way they know how they'll react in a real situation," Walden said. "That way, mistakes can be corrected now instead of mistakes being made when it really happens."

Walden said all district police are going through the training. He said he’d rather be proactive than reactive when it comes to the possibility of an active shooter in a school.

The CBP officers at that training all work at the Donna or the Progreso bridge.

Donna city police will also go through the course.